Hydrogenation of liquid carbonaceous materials



Sept 1947- B. s. GREENSFELDER HYDROGENATION OF LIQUID CARBONACEOUSMATERIALS Filed July 17, 1944 LEOO .wTuLo w mczomsmvr. 175500 cwmoLwm OPx5 comtucmwoLnm 2 Bernard 5. GreenSFelder 8 his Aflomeg M Inveni'or,ieta

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lE' s'r 2,426,929 iaocam's'rron or W GEQUS MATERIALS Bernard 8.Greensfelder, Oaklandnilaliik, assignor to Shell Development Company,San. Francisco, Califr, a corporation of Delaware 7 Application July 17,1944, s No. 545,401

This invention relate to the productionof useful materials by thehydrogenation of petroleum residues, shale oil, heavy hydrocarbon oils.the

liquid products of destructive distillation, carbonization, extraction,or other suitable treatment of' coal, asphalts, pitches and organicsubstances;

and related normally liquid carbonaceous mate- Claims. (011. 196-73).pable of providing the necessary hydrogen for rials, It dealsparticularly with a new and more advantageous method of carrying outsuch conversions whereby operability may be improved and plantefliciency increased. 1 Y

Many different methods for the hydrogenation .of higher boiling normallyliquid carbonaceous materials have been suggested. Virtuallyall' of theproposed methods have been based uponthe reaction of the liquidcarbonaceous material with gaseous molecular hydrogen and have involvedthe use of hydrogenation catalysts. One procedure which has'been favoredby many inventors comprises hydrogenation in the liquid phase usingfinely divided catalyst suspended. in a carbonaceous liquid residue. Theuse of larger catalyst particles disposed in a fixed bed through which aliquid residue is passed under hydrogen pressure has also beenadvocated. In either of these types ofioperation chemical and mechanicaldifllculties are encountered. With suspended catalysts, for

example, recovery of the catalyst from the hy- .drogenatedresiduesleaving the system involves cumbersome extractive processes, while fixedbed catalysts quickly become impregnated with carbonaceous deposits sothat decarbonizing operations are required after relatively shortprocessing the reaction, instead of depending upon 'hydro- 'genationwith gaseou hydrogen.- The elimination of hydrogenation catalysts in thefirst hy- 10- ,drogenation stage of treatmentobviates the dullcultiesencountered in recovery and/or regeneration of catalyst which arecharacteristic of previous methods of hydrogenating this type ofmaterial. After it has given up its transferable By?- drogen the carrieris separately hydrogenated and v recycled to the reaction. Either orboth of these hydrogenation steps may be carried out in a plurali ty ofstages and the use of catalysts in one or more stages pf the first stepemploying a hygo drogen carrier may be desirable aswill be pointed outmore fully hereinafter.

A hydrogen carriers for the processof the invention, partly or whollyhydrogenated aromatic derivatives which are readily separated and g5recovered after they have given up their hydrogen are preferred.Particularly advantageous are, for example, the partly or whollysaturated hydrogenation product of benzene, naphthalene,

methyl naphthtalene, dimethyl' naphthalene, in-

dan, anthracene, phenanthrene and homologs thereof. Products of completehydrogenation of periods. Both of these procedures for dealingwith'spent catalysts reduce overall plant eiilciency.

One of the objects of the present invention is to overcome the foregoingand other disadvantages of prior methods of hydrogenating higher boilingliquid carbonaceous materials. More spefically, one object or theinvention is to entirely avoid or at least to reduce the laboriousprocedures of catalyst recovery and/or regeneration in such processes.Another object is to provide a process whereby carbonaceous materialsmay be converted 45 ing upon the particular materials involved and tolower boiling hydrocarbons more efiectively and at higher rates ofconversion than heretofore. Still another object is to'carry out suchprocesses in a plurality of stages each operated under the mostappropriate conditions. to secure overall optimum results-.- Furtherobjects and advantages of the new process will be apparent from thefollowing description of the preferred methods of applying theprinciples of the invention.

such-aromatic hydrocarbons are'not necessary, as

partially saturated products are also effective,

although the proportional amount of carrier which will be required willof course depend upon its content of transferable hydrogen. Suchcarriers may be readily recovered from the hydrogenation products byfractionation. Chemical treatment to remove sulfur, oxygen or nitrogencompounds or other undesirable impurities and/ or solvent extraction toseparate the aromatic compound or compounds from aliphatic hydrocarbonspresent therewith may be advantageous prior to the rehydrogenation stepof. the process dependthe rehydrogenation procedure adopted.

A wide variety of methods may be used for rehydrogenation" of thehydrogen carrier. Hydro-' genation catalysts such as tungsten,molybdenum and nickel sulfides. or combinations thereof, are

particularly suitable because 'of their immunity to poisoning byimpurities, particularly sulfur compounds, in the feed; However, otherhydrov genating catalysts such as active metals or oxides According tothe present invention, the use of u may be used. Thus, for example,Baney nickel lower pressures,

.tact with the hydrogen carrier. v material'may also containdispersedsolids which 15 ferred for directly hydrogenatirig the feedstock.

adaaeao' I alumina, etc., may also be employed.

-of the invention.

The reaction conditions which will be most suitable for therehydrogenation will depend upon the hydrogen carrier chosen-and thecatalyst used therewith. With the preferred metal sulfide catalysts,naphthalene type hydrogen carriers are advantageously hydrogenated attemperatures of about 150 C. to 500 C, using a substantialstoichiometric excess of hydrogen under a pressure or about 10 to 400atmospheres. With more active catalysts such as reduced nickel, forexample,

for instance, about 1 to 10 atmospheres, are suitable.

The resulting hydrogenated aromatic derivatlve is added to thecarbonaceous material to be hydrogenated in an amount sufilcient toyield the requisite amount of hydrogen for the desired conversion. Incalculating the amount to add it may be generally assumed that thecarrier will be converted to the original aromatic compound but undersome reaction conditions less complete liberation of hydrogen may takeplace and consequently more hydrogen carrier should be used. In general,the quantity of hydrogen requiredwill vary from less than 1% by wei htof the charge for certain petroleum oils up to the range of about 5% tofor asphalts. pitches, tars and the like. Usually it will be'preferablto employ an amount of hydrogen carrier in excess of that required tosupply the minimum amount.

of hydrogen necessary. For example, when using decahydronaphthalene asthe hydrogen carrier, it is generally advantageous to employ betweenabout 0.05 and 2.0 volumes of.the carrier per volume of liquidcarbonaceous material being hydrogenated. With less completelyhydrogenated hydrogen carriers, larger proportions. of carrier aredesirable and it is preferred to usetetrahydronaphthalene, for example,in a ratio of about 0.125 to 5.0 volumes per volume ofliquid feed stock.The resulting mixture of hydrogen carrier and carbonaceous material tobe treated is pas ed through a hydrogenation reactor, preferablytogether with free hydrogen. At a temperature above 300 C. and withpressures above about 40 atmospheres the desired conversion may beetfected in'from one-half minute to about 8 hours depending upon thereactants and catalysts involved Lower temperatures give less efilcientconversion and temperatures higher than about 550 C. are preferably notused because they gen-1 erally tend to cause excessive cracking andproduce an undesirable amount of low boiling mate-.

rials which may complicate subsequent recovery .4 do not substantiallyinterfere with the process material being hydrogenated, for examplenaphthalene, cresol, or their homologs, may be also added at'this point.This treatment may in itself be effected in a series of operations atsuccessively higher temperatures with separation of insoluble materialafter at least the last treatment. With certain liquid carbonaceousmaterials such operations may not be necessary but even in such cases itis desirable to preheat the feed before introducing .it into thehydrogenatlng unit. In accordance with the invention, at least the firststage of the hydrogenaticn is carried out noncatalytically underv thepreviously indicated operating conditions. In

this stage hydrogen is transferred from the hy-.

drogen carrier to. the carbonaceous material being treated. No problemof catalyst decarbonization or catalyst recoveryfrom heavy residues,leaving this stage is encountered and the product has a materiallyincreased fluidity and stability which greatly facilitate furthertreatment. A later stage or stages of hydrogenation may accordingly beadvantageously carried out in the presence of-hydrogen and catalystswhich pros mote simultaneous rehydrogenation of the hydrogen carrier andhydrogenation of the material undergoing treatment. Operations withcatalyst in a fixed bed are especially advantageous for this purpose.Preferred catalysts are sulfides of tungsten, nickel, iron, cobalt andmolybdenum" or mixtures of two or more such sulfide cat alysts. Thecorresponding oxides of such metals or the sulfides and/or oxides ofchromium, titanium, vanadium, manganese, co1umbium, etc.,

. or oxides of silicon. aluminum, boron, magnesium, zirconium and zincmay also be used. Mixtures of these catalysts, especially alumina-boricoxide mixtures with or-without sulfides of tungstn, nickel 'or thelike.are advantageous. Sulfide and oxide catalysts may, for example, beformed in place by reaction of the free metals or alloys thereofv withsulfur and oxygen compounds in the oil being treated. It is also feasiofthe hydrogen carrier. Free hydrogen in a mean ing benefit. It ispossible, and in some cases may be advantageous, to omit the use ofhydrogen and to maintain the desired pressure by other workable means.

The hydrogenation of the'carbonacecus feedstock may be advantageouslycarried out in. several stages. Where asphaltic or heavy residualpetroleum components are being treated these are preferably firstbroughtinto a proper state of fluidity, forexample by heating attemperatures up to about 550 C. in intimate con- -The starting ble tovuse catalysts such as tin or lead and halogens such as iodine. chlorineor bromine, or compounds of these elements, such, for example, as tinhalides or sulfides or the like which may be added in minimal amounts,for example 0.5% by weight or preferably less, to the carbonaceousfeedstock Fixed catalysts, particularly sixth and eighth group metalsulfides, may also be advantageous even when using catalysts addedto thefeedstock. Where more than one catalytic hydrogenation treatment isemployed the catalysts in the difierent stages may be the same or maybediflerent. For example, the first such stage' may be one in whichrehydrogenation of the hydrogen carrier is the reaction predominantlyfavored while the next stage may be one in which transfer of hydrogenfrom the carrier .to the material undergoing'treatment is mainlypromoted, and a third stage may be one in which the direct hydrogenationof the feedstock is effectively catalyzed. ,In such methods of operationcatalysts, such as tin and the halogens, or their compounds, areespecially suitable for promoting the carrier rehydrogenationconcurrently with the hydrogen transfer reaction, while sixth or eighthgroup metal sulfides are pre- Other suitable compounds which aremiscible with tlie' liquid carbonaceous amount of catalysts used therein(if any), the nature of the carbonaceous material being treated and theparticular hydrogen carriers chosen, but in general will be within theranges previously indicated. In all cases it is preferred. to

carry out the catalytic step or steps of the process with a substantialexcess of hydrogen present.

An alternative procedure which offers. advantages 'in some cases is toemploy in the catalytic stage or stages of the process a combination ofcatalysts which promote both hydrogen transfer and rehydrogenation ofthe carrier, as well as direct hydrogenation of the feedstock. Thus, forexample, a fixed bed of tungsten and molybdenum sulfide catalyst may beused with a feed containing a small amount of stannous hydroxide. Suchmethods of operation have the advantage of reducing the number ofhydrogenation stages necessary but involve some sacrifice, in that theahydrogenated aromatic hydrocarbon such, for example, as ahydronaphthalene rromline 8. The hydrogen,'or other gas, from a sourcenot shown, is introduced by line 8 to a compressor l0 capable ofproducing'pressures up to200 to 800 atmospheres and is preheated inheater I l before passing to line 1; Line 41 is provided for introducinginto the feed'mixture any of the previously mentioned fluidityincreasing agents, such as cresol, naphthalene, etc., which it may bedesirable to add. The mixture of heavy oil, hydroaromaticv compound,hydrogen and other added compounds, it any are used, passes throughreactor I! where it is maintained at a temperature exceeding 300 C., bymeans not shown, for about 10 to 150 minutes. Reactor I! mayadvantageously be a closed cylinder of suitable construction towithstand the applied pressure or may be a coil of pressure resistantpiping or. may have other forms. With cylindrical type reactors, packingwhich will promote turbulent most appropriate condition for each of theseveral reactions involved in the process cannot usually be applied.When finely divided catalyst is added to the feed, it very generallymust be recovered for economic reasons. However, the process of theinvention offers the advantage that even in such cases, the recovery andreclamation of the catalyst are easier and less expensive because boththe catalyst and product are much less contaminated with coke, polymersand insolubles due to the initial noncatalytic treatment. A

similar advantage is obtained in the method of operation employingcatalysts in the form of a fixed bed which may be reactivated in Place,or as a moving bed of catalyst which may be continuously reactivated andreturned to the process without interrupting the hydrogenation. The useof powdered or fluid type catalysts is also within the scope of theinvention.

As a rule when only one catalytic hydrogenation stage is to beused, itis preferred that it be operated so as to favor rehydrogenation of thehydrogen carriers employed, since as previously pointed out, thecarriers are preferably aromatic derivatives which are able to transferhydrogen to the feedstock in the absence of added catalysts. Thiscatalytic rehydrogenation stage may be operated under conditions moreintense, especially with respect to temperature, than the firstnoncatalytic stage, since the feedstock has been partially hydrogenatedand has thus been rendered more stable. It is sometimes preferred'thatthe last stage in the hydrogenation treatment be noncatalytic, at leastwith respect to h'yrogenation of the carrier, in order to utilize alltransferable hy. drogen in the carrier by favoring its conversion to theoriginal aromatic compound. This conversion will also facilitate itsrecovery and most effective separate rehydrogenation.

The attached drawing shows, diagrammatically, an assemblage ofapparatus, not drawn to scale, suitable for the treatment of heavy oilsaccording to one of the preferred-forms of the invention.

As shown in the drawing, the liquid feedstock is supplied by a line I,from a source not shown,

flow -of the reaction mixture is advantageous. Metal turnings areparticularly suitable for such packing because they also act as heattransfer media and help to maintain a more uniform rehydrogen from thehydroaromatic carrier to the feedstock. It will be understood thatsuitable metering devices or other means, not shown, are provided tocontrol the flows of all materials entering the system and to insurethat a proper proportion of hydroaromatic compound from line I mixeswith the feedstock to supply sufflcient hydrogen for the desired extentof reaction.

The reaction products from unit If, pass by lines I! and It to line I!feeding into reactor l6. Separate quantities of hydrogen andhydroaromatic compound, may if desired, be introduced by lines l1 and i8respectively. Reactor I6 is preferably packed with a suitablehydrogenation catalyst, for example. tin sulfide on a support, althoughother types of catalyst, as previously indicated, may be used and it isalso feasible to use catalysts in a finely divided form, for whichpurpose a supply line I! is provided. As a rule it is preferable to feedthe products of reactor It to reactor it via lines I! and 20 feeding togas separator 2i and residue separator 22 from which coke, insolubles,etc., issuing from the first stage are removed by line 28. The separatedhydrocarbons may then hated by pump 24 to line l5. Where suspendedinstead of fixed catalysts are used in reactor l8, similar-means, notshown, are also provided for recovering the added catalyst from theeilluent of the reactor withdrawn by line 25. With the-alternative fixedcatalyst the reaction mixture may be' passed directly from line 25 toline 26 feeding reactor 21. Reactor 2'! may be of the same form asreactor I! since its most important function is the transfer of hydrogenfrom hydroaromatic compound either remaining unreacted from reactors l2and It or formed by T rehydrogenation in reactor l8, and notsubsequently fullydehydrogenated therein, to the hy-' ll carbon present.

drocarbons undergoing treatment. Additional hydrogen may be supplied toreactor 21 by line 28 and somewhat more drastic reaction condi-' tionsmay be maintained therein than are used in reactors I2 and II in orderto bring about more complete conversion of the hydroaromatic hydro-Reaction products from nonsome catalytic unit 21 pass by line to gassepara r which advantageously is maintained at a temperature andpressure suitable for separation of all products lower boiling than theadded hydrogen carrier in any of its states of hydrogenation. Such lowerboiling products are removed by line 3| to cooler 32 to which similarproducts from units l2 and I6 may also be fed if separation between eachstage is being employed as previously described. The cooled lowerboiling products are treated in the usual way for separation of thehydrogen which may be returned to line 9 while the hydrocarbons,including the gasoline boiling products are sent to storage. The higherboiling products from separator 30 are fed by line 33 'to a distillationunit 34 which may comprise more than the one still shown, wherein thehydrogen carriers are taken off overhead by line 35 and are fed togetherwith preheated hydrogen from heater II to catalytic hydrogenationreactor 36 which is preferably supplied with a sixth and/or eighth groupmetal sulfide catalyst and is maintained at a temperature of about 150C. to 500 C. and under a pressure of about 10 to 400 atmospheres. Theexcess hydrogen is separated-from products of this reaction in gasseparator 31 and withdrawn by line 38 while the hydroarom-atic productsare removed by line 39 and fed to lines 8 and I8 for reuse in theprocess as previously described. Higher boiling products of about 300 C.to 375 C. end point are removed by line 40 and may be either conveyed byline II to storage prior to fractionation, final treatment and use asburner oil, premium fuel oil, Diesel oil, or for the manufacture of highquality oils for special usages etc., or may be passed through line 42to cracking units, not shown, where they may be reacted, either with orwithout hydrogen and in either the presence or absence of catalysts, toobtain increased yields of lower boiling hydrocarbons. Higher boilingproducts are taken off as bottom product by line 43 and conducted to aseparating zone 44 which may advantageously include mechanical or othermeans for removing coke and any other constituents of limited solubilitywhich are taken oif-by line 45. The remaining heavy oil is then recycledby line 46 to mix with the feed in line 3. It will be seen that theprocess of the invention offers many advantages over prior methods ofhydrogenating carbonaceous materials, particularly in regard to theemcienoy and facility of operation which results from the use of ahydrogen carrier capable of effecting the desired hydrogenation undernoncatalytic conditions and with respect-to the improved quality ofproducts obtained by carrying out the operations in a series of stepseach controlled so that the individual reactions or separate groups ofreactions are effected under the conditions most favorable therefor. Theprocess is especially adapted for the hydrogenation of high boilingnormally liquid carbonaceous materials containing at least 5% hydrogenby weight. With feedstocks of lower hydrogen content larger amounts ofhydrogen carrier must be circulated to achieve the same result and thenet capacity of the apparatus is correspondingly reduced.

The invention is capable of extensive variation not only in relation tothe carbonaceous feedstocks which may be used but also in the details ofoperation employed. For example, instead of, or in addition to thefractionation procedure described for recovery of the hydrogen carrier,solvent extraction methods using liquid sulfur genation or between thedifferent stages'of catastead of the separation following the last stageof lytic hydrogenation either in addition to or intreating. Whether ornot such intermediate separations are made, it may bedesirable to addhy-' drogen carrier to other hydrogenation stages than the first. Stillother variations in the process may be made without departing from theprinciples of the invention which, it will be seen, is not limited tothe procedures described by way of example nor by any theory advanced inexplanation of the improved results obtained.

I claim as my invention:

1. A method of hydrogenating high boiling carbonaceous material whichcomprises feeding said high boiling carbonaceous material, anaphthalenic hydrogenation product and hydrogen to a reactor maintainedat a temperature of at least 300 0., withdrawing reaction productstherefrom and passing them to a catalyst chamber containing ahydrogenation catalyst under hydrogenating conditions, removing reactedmixture from the catalyst chamber and flowing it through anon-catalyticreaction zone at a temperature and pressure at which hydrogen istransferred from the naphthalenic hydrogenation product present to thecarbonaceous material undergoing treatment, fractionating the reactionproducts to separate an overhead stream containing naphthalenes, amiddle fraction f higher boiling hydrocarbons and a heavier fractioncontaining residual solids. removing said residual solids from thelatter, recycling at least a part of the remaining hydrocarbon contentto the first reaction stage and separately hydrogenating thenaphthalenes present in said overhead stream to produce saidnaphthalenic hydrogenation product for said reaction.

2. A method of hydrogenating high boiling carbonaceous material whichcomprises feeding said high boiling carbonaceous material, an aromatichydrocarbon hydrogenation product and hydrogen to a reactor maintainedat a temperature of at least 300 0., withdrawing reaction productstherefrom and passing them to a catalyst chamber containing ahydrogenation catalyst under hydrogenating conditions, removing reactedmixture from the catalyst chamber and flowing it through a noncatalyticreaction zone at a temperature and pressure at which hydrogen istransferred from the aromatic hydrocarbon hydrogenation product presentto the carbonaceous material undergoing treatment, fractionating thereaction products to separate a stream containing the dehydrogenationproduct of said aromatic hydrocarbon hydrogenation product, a fractioncontaining hydrogenation products of the reaction and a higher boilingfraction, recycling at least a part of the latter to the first reactionstage and separately hydrogenating said dehydrogenation product toproduce the aromatic hydrocarbon hydrogenation product for saidreaction.

3. A method of hydrogenating high boiling carbonaceous material whichcomprises feeding said high boiling carbonaceous material, an aromatichydrocarbon hydrogenation product and hydrogen to a reactor maintainedat a temperature of 300 C. to 550 C., withdrawing reaction productstherefrom and passing them to .a catalyst chamber containing ahydrogenation cata-' V lyst under hydrogenating conditions, removingreacted mixture from the catalyst chamber and flowing it through anon-catalytic reaction zone at a temperature and pressure at whichhydrogen is transferred from the aromatic hydrocarbon hydrogenationproduct present to the carbonaceous material undergoing treatmentfractionating the reaction products to separate a fraction con,- taininghydrogenation products of th reaction from higher boiling hydrocarbonscontaining residual solids, removing said residiual solids from thelatter, and recycling at' least a part of the remaining hydrocarboncontent to the first reaction stage.

4. A method of hydrogenating-high boiling carbonaceous material whichcomprises feeding said high boiling carbonaceous material, an aromatichydrocarbon hydrogenation product and hydrogen to a reactor maintainedat'a temperature of 300 C. to 550 0., withdrawing reaction productstherefrom and passing them to a catalyst chamber containing ahydrogenation catalyst under hydrogenating conditions, removing reactedmixtur from'the catalyst chamber and flowing it through a non-catalyticreaction zone at a temperature and pressure at which hydrogen istransferred from the aromatic hydrocarbon hydrogenation product presentto the carbonaceous material undergoing treatment, fractionating thereaction products to separate a stream containing the dehydrogenationproduct of said reaction from a fraction containing hydrogenatedhydrocarbons produced therein and'hydrogenating said separateddehydrogenation product to produce said aromatic hydrocarbonhydrogenation product for use in the first reaction stage.

5. A method of hydrogenating high boiling carbonaceous material whichcomprises feeding said high boiling carbonaceous material, a.hydroaromatic hydrocarbon and hydrogen to a reactor maintained at atemperature of 300" C. to 550 C., withdrawing reaction productstherefrom and passing them to a catalyst chamber containing ahydrogenation catalyst under hydrogenating conditions, removing reactedmixture from. the

- catalyst chamber and flowing it through a noncatalytic reaction zoneat a temperature and pressure at which hydrogen is transferred from thehydroaromatic hydrocarbon present to the carbonaceous materialundergoing treatment, and fractionating the reaction products to recovera fraction containing hydrogenation products of I the reaction.

BERNARD S. GREENSFELDER.

aarmsnoas orrnn The following references are of record in the file ofthis patent:

UNITED STATES. PATENTs France Mar. 10, 192'!

